2 ms·

So the issue really is that the match-and-discard wildcard uses a spelling that would otherwise be a valid identifier name causing an ambiguity to the reader,

So the issue really is that the match-and-discard wildcard uses a spelling that would otherwise be a valid identifier name causing an ambiguity to the reader, if not to the compiler. In retrospect using a different character (say '*') would have been better, clueing the reader that something different was happening; but I guess there is long history of this use of _ in ML languages.

steveklabnik 2y ago
I mean, it’s never a valid identifier, and that is spelled out in the reference too.
- gpderetta 2y ago
  of course it isn't, it acts as a keyword, but it looks like a valid identifier. As this difference doesn't matter 99% of the time, it can be be easily overlooked, becoming a pitfall the 1% that matters. Of course it too late to change it, but pointing it is a must. I understand rust has a linter pass specifically to catch this sort of issues.